diff --git a/src/go/internal/gcimporter/gcimporter_test.go b/src/go/internal/gcimporter/gcimporter_test.go
index a8745eea3e..308f93e8bd 100644
--- a/src/go/internal/gcimporter/gcimporter_test.go
+++ b/src/go/internal/gcimporter/gcimporter_test.go
@@ -530,6 +530,27 @@ func TestIssue25301(t *testing.T) {
 	importPkg(t, "./testdata/issue25301")
 }
 
+func TestIssue25596(t *testing.T) {
+	skipSpecialPlatforms(t)
+
+	// This package only handles gc export data.
+	if runtime.Compiler != "gc" {
+		t.Skipf("gc-built packages not available (compiler = %s)", runtime.Compiler)
+	}
+
+	// On windows, we have to set the -D option for the compiler to avoid having a drive
+	// letter and an illegal ':' in the import path - just skip it (see also issue #3483).
+	if runtime.GOOS == "windows" {
+		t.Skip("avoid dealing with relative paths/drive letters on windows")
+	}
+
+	if f := compile(t, "testdata", "issue25596.go"); f != "" {
+		defer os.Remove(f)
+	}
+
+	importPkg(t, "./testdata/issue25596")
+}
+
 func importPkg(t *testing.T, path string) *types.Package {
 	pkg, err := Import(make(map[string]*types.Package), path, ".", nil)
 	if err != nil {
diff --git a/src/go/internal/gcimporter/testdata/issue25596.go b/src/go/internal/gcimporter/testdata/issue25596.go
new file mode 100644
index 0000000000..8923373e5f
--- /dev/null
+++ b/src/go/internal/gcimporter/testdata/issue25596.go
@@ -0,0 +1,13 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package issue25596
+
+type E interface {
+	M() T
+}
+
+type T interface {
+	E
+}
diff --git a/src/go/types/type.go b/src/go/types/type.go
index f274e30ab6..cc87f1edb5 100644
--- a/src/go/types/type.go
+++ b/src/go/types/type.go
@@ -275,7 +275,9 @@ func NewInterface(methods []*Func, embeddeds []*Named) *Interface {
 }
 
 // NewInterface2 returns a new (incomplete) interface for the given methods and embedded types.
-// Each embedded type must have an underlying type of interface type.
+// Each embedded type must have an underlying type of interface type (this property is not
+// verified for defined types, which may be in the process of being set up and which don't
+// have a valid underlying type yet).
 // NewInterface2 takes ownership of the provided methods and may modify their types by setting
 // missing receivers. To compute the method set of the interface, Complete must be called.
 func NewInterface2(methods []*Func, embeddeds []Type) *Interface {
@@ -298,8 +300,12 @@ func NewInterface2(methods []*Func, embeddeds []Type) *Interface {
 	sort.Sort(byUniqueMethodName(methods))
 
 	if len(embeddeds) > 0 {
+		// All embedded types should be interfaces; however, defined types
+		// may not yet be fully resolved. Only verify that non-defined types
+		// are interfaces. This matches the behavior of the code before the
+		// fix for #25301 (issue #25596).
 		for _, t := range embeddeds {
-			if !IsInterface(t) {
+			if _, ok := t.(*Named); !ok && !IsInterface(t) {
 				panic("embedded type is not an interface")
 			}
 		}